The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

Was Putin in social Siberia for G20 snap?

There was plenty of distance between Tony Abbott and Vladimir Putin when world leaders lined up for the traditional G20 "family" photo.

The bellicose Russian leader was positioned in the front far right-hand corner, with South African President Jacob Zuma on his left.

There was no repeat of the awkward arrangement at the APEC meeting in Beijing earlier this week when the prime minister was lined up one row above and behind Mr Putin, leaving Mr Abbott staring morosely at his leader colleague.

Mr Abbott hadn't yet delivered on his promise to "shirt-front" Mr Putin over Russia's suspected involvement in MH17 disaster, which killed 298 including 38 Australians, so the placement was especially tense.

This time Mr Abbott had the diplomatic upper hand - so to speak - because Australia holds the current G20 presidency.

He was front row and centre for the official G20 snap, flanked by top-two trading partners - China and Japan.

The leaders of Canada, Indonesia, UK and India - with whom Mr Abbott has good relationships - stood shoulder to shoulder behind him.